From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 511E2C43458 for ; Wed, 1 Jul 2026 23:34:26 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 2F78810EF9A; Wed, 1 Jul 2026 23:34:25 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=Nvidia.com header.i=@Nvidia.com header.b="Rqnge0Li"; dkim-atps=neutral Received: from PH0PR06CU001.outbound.protection.outlook.com (mail-westus3azon11011014.outbound.protection.outlook.com [40.107.208.14]) by gabe.freedesktop.org (Postfix) with ESMTPS id 8D41E10E3F4 for ; Wed, 1 Jul 2026 23:34:23 +0000 (UTC) ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=SRjX7QYNKHtRNosqFAcpOOAdkJzei76cSowZ7QKYAM21AQqqyW+hcYapN83IWyMuT9i7OGL2JIiYP/e/welWdmH/MlD8wEXZVt5PSvZPrSZOV0g8joh9hk53/eNB+Wsa7RI+4FkOg/U6a1MdpVXX8Z1poluq29YPL/HOjFs+GNyNw1l2NwuNZENheysP69E15DWaIr1Ufk5WMIAhNudSfjJ/vjYxV69GLrWCwQ2+PHbc/Dth6ue7TKR0lLGort/wgUlG3fLlGEdqtjK8NXGt5bCMSITUylZyeqNlXqYzzNgnj+xL05GBSkgz45ckaTLPPAsew0CwPRHWMaYuKQw98A== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=51hBTdzk8fR2gicwYbqOuDDMAvqwrDd3yVNYSY2WmfA=; b=D5oDk7QkLT/QYUnxP3WK/rEb/RJ04BWmE/GkH9plpUUDGCkPGbZmySVZirL8C1JYoJ6vy18cFcrtznmCaA+Wo4C/f14fcWaaut57lknRjMpkJkxSm3S5QLHWvjgT3cOWI8PAbiYOgMfZrLCL7rEg3FdkLh7TsQpSfR2PrpFvOFpbDCuaoM93QYYvMeKRVOuXBWL6HdLD7Oajp2ouBBXWba8QkZqAD+htSP0Ml6k/3FPFGr8s39aJ1avo7LO99CKs6Ip9UwBqgU842ZZQZnXZGl5Q7Yo0nDm2GJEJFcNJ2Ga02js6ok4z4gG4TT01cFBt99r6r+pFqh6TNtCmXZ0d6g== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=nvidia.com; dmarc=pass action=none header.from=nvidia.com; dkim=pass header.d=nvidia.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=Nvidia.com; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=51hBTdzk8fR2gicwYbqOuDDMAvqwrDd3yVNYSY2WmfA=; b=Rqnge0LiJ+i8hgR9x52Rx3EZXQN5C1hOmCMeN7/cbENTTULRNrALI307AZ9MNw0EEqtHcjT36dUc0CVA4iCrNI/5fHJxLfN6fMpuG/8txXpWyFnjDELeswozXdMhUcXvtYP7z+2wKcV+ekyU4WFBunLH5h2hm2byuYAIJ1y0QVeGhwShJ6hWl3w/xKO7yIrBv2G4sC3ztjgHjI1xfpaX/QCOR+iH7FQCGHEsV8XbEo+3wKD2sSAxnKTL/qt0Lf6vJBa8Q8kTjl1VTLZHcTmVr7/Gv4e+S44pnD9FnGYdabX3AgJ+R4mBUhwXThYjdQoR7+ZwC203khf300N49ibymQ== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from LV8PR12MB9620.namprd12.prod.outlook.com (2603:10b6:408:2a1::19) by LV0PR12MB999093.namprd12.prod.outlook.com (2603:10b6:408:32e::21) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.181.9; Wed, 1 Jul 2026 23:34:20 +0000 Received: from LV8PR12MB9620.namprd12.prod.outlook.com ([fe80::299d:f5e0:3550:1528]) by LV8PR12MB9620.namprd12.prod.outlook.com ([fe80::299d:f5e0:3550:1528%4]) with mapi id 15.21.0181.008; Wed, 1 Jul 2026 23:34:20 +0000 Date: Wed, 1 Jul 2026 20:34:19 -0300 From: Jason Gunthorpe To: Alistair Popple Cc: Matthew Brost , Dave Airlie , dri-devel , iommu@lists.linux-foundation.org, "Koenig, Christian" Subject: Re: iommu/smmu/PCI ATS + TTM unmaps + nouveau best way forward Message-ID: <20260701233419.GK7481@nvidia.com> References: <20260630113919.GC7481@nvidia.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-ClientProxiedBy: YT4PR01CA0300.CANPRD01.PROD.OUTLOOK.COM (2603:10b6:b01:10e::25) To LV8PR12MB9620.namprd12.prod.outlook.com (2603:10b6:408:2a1::19) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: LV8PR12MB9620:EE_|LV0PR12MB999093:EE_ X-MS-Office365-Filtering-Correlation-Id: b78ced28-f0cc-433d-94c0-08ded7c94629 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; ARA:13230040|366016|23010399003|376014|1800799024|4143699003|56012099006|11063799006|22082099003|18002099003; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255; CTRY:; LANG:en; SCL:1; SRV:; IPV:NLI; SFV:NSPM; H:LV8PR12MB9620.namprd12.prod.outlook.com; PTR:; CAT:NONE; SFS:(13230040)(366016)(23010399003)(376014)(1800799024)(4143699003)(56012099006)(11063799006)(22082099003)(18002099003); DIR:OUT; SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?A8X1Boxn2aMxbozDzlwySyPXbNKHgkSmAEXp8jGd9SPUXzUBhU0Q9yV/hHF1?= =?us-ascii?Q?2uFM+nBKaOVHOCq7VCYWhQ5oRwj9QtR0y9mEaf84QT3n8TLk10ShqGnIDNb6?= =?us-ascii?Q?tD7A2KXp7hfsrjGQSA0e53LN1j4tTycP/cw/+Ov0nTMRHmjbmVlSkFrUGAFT?= =?us-ascii?Q?NWdtzzMN38sNMAJ089J/8Nyeoq/qp5GaJkECVRE5yl4GdgSDHmctVmGUtmvD?= =?us-ascii?Q?X5xpetReWrbk0YRbDcijI5e0Pibq/vgsTlsCxYjRS7VnzLEOd/hk+OKg1lsB?= =?us-ascii?Q?4vUGKzrRqb3NwSbUwxDt9OvW+ReH+z3fscQYZUE/CihyQOLKg3HBV9ozP82h?= =?us-ascii?Q?47oXJRdjD/3cSzDPg+3NFlOd07t+D/Ob4KTv2s/Iafs6Txqo4iY7iYecC49w?= =?us-ascii?Q?DbH1o5fS9f047D3QJ9xE8wl2OisNTk/sQ/t2xXSIjH7Mz4GSacA0bCXM0ZA0?= =?us-ascii?Q?aNPqF4jxWeJ6yYS+t13kw148CldKQkm9dOOdZCDqsBA5hMEGCgyJA52axbrw?= =?us-ascii?Q?gQgCjbvy9VhSQXTJpKrfO9gh1pjIVfwCnTZEdsztyj9Jm+t1FNznuTP867jL?= =?us-ascii?Q?KWPAZFiS84oCtPZxjR9qmmp/GEXb80uSMIjygfKuYhILCwjfTPFecHAbrqzx?= =?us-ascii?Q?GwOx/FydcILKblnAgNdS9tDePlcNxy1xa4TmIbZdTeCI4R+OznhTLVUdYkaI?= =?us-ascii?Q?2set/fSDSo3eIqrg99/CaAydRwc2vWOgo2xsrHMiGKIrDD1WwhncWPDVTVED?= =?us-ascii?Q?0wcJ21WckUAGAtZZvTGCbWxln/fCY1cs/OT481ZpS0TQX2o4b/0ciExy9cP1?= =?us-ascii?Q?ebSpDRSFnmCdQF8lmICEeCmCYdziZqVPClITwsrWEfgqSg/NJ9a6zICY248Y?= =?us-ascii?Q?dNRE8jDJNOnjFxJKCBCuyM/VeQbqkrUq/anwdq8UzoviL/hSy2BudDxJdQKB?= =?us-ascii?Q?bEgucPE0Z3ly4/0Ab3FADPnOOmw6K23sz4zq8PkM2Nby+BnqzVk+LvkeG1m6?= =?us-ascii?Q?TiI7Jwdkmy5wS4NDYYPBXWTIZk6VyYMAtpGBLY9HPFDF4njduHLAmnT/uB1H?= =?us-ascii?Q?OCSrnBq431k+YP8T6e/pTOneff6JR+GAHfOWl4UST9g/tJ7lCBD93YmBZjT2?= =?us-ascii?Q?2/Sp3qk6rlomhaD3X5QNqIFQm+ZtgYRiTmyO63C5fkWL3mUyDDSp3QvyTg+C?= =?us-ascii?Q?n2Y1sbtqjKbrGvBeukszJ4tIEl2fJngDgHSdJure6JsBpXi2X4hUnnMqRL97?= =?us-ascii?Q?Ib44eEeI+D13+jZaUzhcmTGlTwSwb+gqGWupnxdTnIdcThNh+RrIVayzw5ds?= =?us-ascii?Q?2UkNrVucERJeZhp9K+f6U0+4L/JqkKZ3GVXmyizoTtSZSBNNBnLYXF5B1R/I?= =?us-ascii?Q?S2aA1crYmNafkoOyYRMhOVyauZxvske5EFmlvdVle1z5K9VBnJ1QnfTf3gmQ?= =?us-ascii?Q?ousuMFusEjqA692AKvicWrpC+p90gZQ9rOtPpCKA9nYi/RzQCWjRDn7LG9tD?= =?us-ascii?Q?GPHOno7+8yo+nxR58qYoZeyN0SV/W2kcPn+lqSaR8zsYJyn7p0VffX12+uaP?= =?us-ascii?Q?lLA/cZGjSIzYIDom9/pqnbrs+DaUeyRkyRc5iM6IC1y/m4hcaPSP8QpoQG3S?= =?us-ascii?Q?T6z9Dta/d6+hRMaBWo4gfpzECTABAcn3QNHRahcggJTKJmbvd6Ba77Veh9ER?= =?us-ascii?Q?tSX/knGxp21ghF5bq4Vg8e38KRv/fw0ZR3StP1AbDA1q3JxU?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: b78ced28-f0cc-433d-94c0-08ded7c94629 X-MS-Exchange-CrossTenant-AuthSource: LV8PR12MB9620.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 01 Jul 2026 23:34:20.2230 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: KuFEdhk55mDtzQ4NlGxT+nhF/975sNqw17cq/qnYmzdExozT7agqMQtid3Ev+qIM X-MS-Exchange-Transport-CrossTenantHeadersStamped: LV0PR12MB999093 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Wed, Jul 01, 2026 at 11:30:08AM +1000, Alistair Popple wrote: > Agree with most of the above and this seems the most likely explaination. ATS > doesn't change much here - most of our driver still goes via dma_map/unmap to > access host memory via an IOMMU IOVA so non-present entries there would be fatal > at the IOMMU level. So even with ATS enabled a non-present DMA mapping should > still result in noisy IOMMU faults. AFAIK, the iommu driver does not log ATS non-present replies, those are considered normal events. The device itself is the only source of reporting. Jason